CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Adjustment	Adjusted Balance	Five Star	Shareholders Five Star	Total Equity Attributable to Common Shareholders	Total Equity Attributable to Common Shareholders Adjusted Balance	Total Equity Attributable to Common Shareholders Shareholders Five Star	Common Shares	Common Shares Adjusted Balance	Additional Paid In Capital	Additional Paid In Capital Adjusted Balance	Cumulative Net Income	Cumulative Net Income Adjustment	Cumulative Net Income Adjusted Balance	Cumulative Other Comprehensive Income (Loss)	Cumulative Other Comprehensive Income (Loss) Adjustment	Cumulative Other Comprehensive Income (Loss) Adjusted Balance	Cumulative Distributions	Cumulative Distributions Adjusted Balance	Cumulative Distributions Shareholders Five Star	Total Equity Attributable to Noncontrolling Interest	Total Equity Attributable to Noncontrolling Interest Adjusted Balance
Balance at Dec. 31, 2017	$ 3,277,188	$ 0	$ 3,277,188			$ 3,104,950	$ 3,104,950		$ 2,376	$ 2,376	$ 4,609,316	$ 4,609,316	$ 1,766,495	$ 87,429	$ 1,853,924	$ 87,231	$ (87,429)	$ (198)	$ (3,360,468)	$ (3,360,468)		$ 172,238	$ 172,238
Balance (in shares) at Dec. 31, 2017									237,630,409	237,630,409
Increase (Decrease) in Shareholders' Equity
Net (loss) income	292,414					286,872							286,872									5,542
Amounts reclassified from cumulative other comprehensive income to net income	0
Equity in unrealized gain (loss) of an investee	(68)					(68)										(68)
Distributions	(370,746)					(370,746)													(370,746)
Share grants	2,515					2,515			$ 1		2,514
Share grants (in shares)									123,800
Share repurchases	(413)					(413)					(413)
Share repurchases (in shares)									(22,999)
Share forfeitures	2					2					2
Share forfeitures (in shares)									(1,310)
Distributions to noncontrolling interest	(21,022)																					(21,022)
Balance (in shares) at Dec. 31, 2018									237,729,900
Balance at Dec. 31, 2018	3,179,870					3,023,112			$ 2,377		4,611,419		2,140,796			(266)			(3,731,214)			156,758
Increase (Decrease) in Shareholders' Equity
Net (loss) income	(82,878)					(88,234)							(88,234)									5,356
Amounts reclassified from cumulative other comprehensive income to net income	175					175										175
Equity in unrealized gain (loss) of an investee	91					91										91
Distributions	(199,719)					(199,719)													(199,719)
Share grants	1,393					1,393			$ 2		1,391
Share grants (in shares)									202,500
Share repurchases	(293)					(293)					(293)
Share repurchases (in shares)									(31,747)
Share forfeitures	(6)					(6)					(6)
Share forfeitures (in shares)									(3,490)
Distributions to noncontrolling interest	$ (21,583)																					(21,583)
Balance (in shares) at Dec. 31, 2019	237,897,163			10,268,158					237,897,163
Balance at Dec. 31, 2019	$ 2,877,050					2,736,519			$ 2,379		4,612,511		2,052,562			0			(3,930,933)			140,531
Increase (Decrease) in Shareholders' Equity
Net (loss) income	(134,307)					(139,453)							(139,453)									5,146
Amounts reclassified from cumulative other comprehensive income to net income	0
Equity in unrealized gain (loss) of an investee	0
Distributions	(42,825)				$ (59,801)	(42,825)		$ (59,801)											(42,825)		$ (59,801)
Share grants	1,574					1,574			$ 4		1,570
Share grants (in shares)									420,000
Share repurchases	(171)					(171)					(171)
Share repurchases (in shares)									(47,375)
Share forfeitures	(6)					(6)					(6)
Share forfeitures (in shares)									(1,310)
Distributions to noncontrolling interest	$ (22,292)																					(22,292)
Balance (in shares) at Dec. 31, 2020	238,268,478								238,268,478
Balance at Dec. 31, 2020	$ 2,619,222					$ 2,495,837			$ 2,383		$ 4,613,904		$ 1,913,109			$ 0			$ (4,033,559)			$ 123,385